User Manual

SCSI Commands Reference Manual, Rev. J 497
www.seagate.com Parameters for direct access devices
5.4.13 Logical Block Provisioning VPD page (82h)
The Logical Block Provisioning VPD page (see table 467) provides the application client with logical block provisioning related
operating parameters of the logical unit.
PERIPHERAL QUALIFIER and PERIPHERAL DEVICE TYPE fields
The PERIPHERAL QUALIFIER field and the PERIPHERAL DEVICE TYPE field are defined in SPC-5.
PAGE CODE field
The PAGE CODE field is defined in SPC-5 and shall be set to the value shown in table 467 for the Logical Block Provisioning VPD page.
PAGE LENGTH field
The PAGE LENGTH field is defined in SPC-5. If the DP bit is set to zero, then the PAGE LENGTH field shall be set to 0004h. If the DP bit is set to
one, then the PAGE LENGTH field shall be set to the value defined in table 467.
THRESHOLD EXPONENT field
The THRESHOLD EXPONENT field set to a non-zero value indicates the threshold set size in LBAs as a power of 2 (i.e., the threshold set size is
equal to 2
(threshold exponent)
). A THRESHOLD EXPONENT field set to zero indicates that the logical unit does not support logical block provision-
ing thresholds.
If logical block provisioning thresholds are supported, then the threshold exponent shall be a non-zero value selected such that:
(capacity ÷ 2
(threshold exponent)
) < 2
(32)
where:
capacity is 1 + the LBA of the last logical block as returned in the READ CAPACITY (16) parameter data (see 3.23.2)
(i.e., the number of logical blocks on the direct access block device);
and
2
(32)
is the constant value 1_0000_0000h (i.e., 4 294 967 296).
LBPU bit
1 A logical block provisioning unmap (LBPU) bit set to one indicates that the device server supports the UNMAP command (see 3.54).
0 An LBPU bit set to zero indicates that the device server does not support the UNMAP command.
Table 467 Logical Block Provisioning VPD page
Bit
Byte
7 6 5 4 3 2 1 0
0 PERIPHERAL QUALIFIER PERIPHERAL DEVICE TYPE
1 PAGE CODE (B2h)
2 (MSB)
PAGE LENGTH (n - 3)
3 (LSB)
4 THRESHOLD EXPONENT
5 LBPU LBPWS LBPWS10 LBPRZ ANC_SUP DP
6 MINIMUM PERCENTAGE PROVISIONING TYPE
7 THRESHOLD PERCENTAGE
8
PROVISIONING GROUP DESCRIPTOR (if any). . .
63